JP6911426B2 - Grinding simulation equipment and method - Google Patents

Description

The present invention relates to a grinding process simulation apparatus and method.

The grinding process is performed, for example, by bringing a grindstone wheel that rotates at high speed into contact with a rotating workpiece. In such grinding, heat energy is generated due to friction between the grindstone and the workpiece. Then, the temperature of the workpiece rises due to this thermal energy. As a result, grinding burn may occur on the workpiece, and grinding burn may remain on the workpiece (product) after the grinding process.

Therefore, in Patent Document 1, the temperature at each depth of the workpiece is calculated based on the total grinding heat energy, the distribution ratio, and the depth of the workpiece, and based on the calculated temperature at each depth of the workpiece. To calculate the grinding burn depth. As a result, it is possible to determine the grinding processing conditions that do not leave grinding burn.

Japanese Patent No. 5262049

In Patent Document 1, the grinding burn depth by the current grinding process is calculated, and the grinding burn depth by the pre-grinding process performed before the current grinding process is not taken into consideration. Therefore, there is a demand for a grinding process simulation that can more accurately calculate the grinding burn depth of a workpiece in the grinding process.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a grinding processing simulation apparatus and method capable of more accurately calculating the grinding burn depth of a workpiece in grinding processing.

The grinding processing simulation device according to this means relatively moves the rotationally driven grind wheel and the rotationally driven workpiece to bring the peripheral surface of the grind wheel into contact with the peripheral surface of the workpiece, and the workpiece. It is a grinding process simulation device that simulates the grinding state of the workpiece in the grinding process for grinding the peripheral surface of the workpiece, and is a relative of the grind wheel and the workpiece in a relative movement direction between the grind wheel and the workpiece. The removal amount calculation unit that calculates the removal amount of the work piece by the grindstone based on the position, the shape of the grind wheel, and the shape of the work piece, and the grinding process based on the calculated removal amount. The grinding resistance calculation unit that calculates the grinding resistance in the above, the calculated grinding resistance, and the thermal energy calculation unit that calculates the grinding heat energy based on the relative speed of the grinding wheel with respect to the workpiece at the grinding point. Be prepared.

Further, based on the calculated grinding heat energy, the contact arc length between the workpiece and the grindstone, and the machining depth of the workpiece, the temperature at the machining depth of the workpiece was calculated and calculated. A grinding burn depth calculation unit that calculates the grinding burn depth of the workpiece based on the temperature of the machining depth of the workpiece, and one rotation before the workpiece when a certain machining point is currently being ground. Based on the grinding burn depth calculated in the grinding of the same machining point (hereinafter referred to as pre-grinding ) and the removal amount calculated in the current grinding of the machining point (hereinafter referred to as current grinding). The new grinding burn depth in the current grinding is calculated based on the calculated grinding burn depth in the current grinding and the calculated grinding burn depth in the current grinding and the grinding burn depth calculated in the current grinding. It is equipped with a new grinding burn depth calculation unit that calculates the value.

In this grinding processing simulation apparatus, the grinding burn depth in the current grinding is calculated based on the grinding burn depth calculated in the pre-grinding and the removal amount calculated in the current grinding. Then, the new grinding burn depth in the current grinding is calculated based on the calculated remaining grinding burn depth in the current grinding and the grinding burn depth calculated in the current grinding. As a result, even if the grinding burn in the pre-grinding cannot be completely removed by the current grinding and remains, the new grinding burn depth in the current grinding is calculated in consideration of the grinding burn-out depth in the current grinding. , The grinding burn depth of the workpiece in the grinding process can be calculated more accurately.

In the grinding processing simulation method according to this means, the rotationally driven grindstone and the rotationally driven workpiece are relatively moved to bring the peripheral surface of the grindstone into contact with the peripheral surface of the workpiece, and the workpiece is said to be in contact with the peripheral surface of the grindstone. This is a grinding process simulation method that simulates the grinding state of the workpiece in the grinding process that grinds the peripheral surface of the work piece, and is a method of simulating the grinding state of the work piece. The removal amount calculation step of calculating the removal amount of the work piece by the grindstone based on the position, the shape of the grindstone, and the shape of the work piece, and the grinding process based on the calculated removal amount. It is provided with a grinding resistance calculation step for calculating the grinding resistance in the above.

Further, a thermal energy calculation step of calculating the grinding heat energy based on the calculated grinding resistance and the relative speed of the grindstone with respect to the workpiece at the grinding point, and the calculated grinding thermal energy and the workpiece. A temperature calculation step of calculating the temperature at the machining depth of the workpiece based on the contact arc length with the grindstone and the machining depth of the workpiece, and the calculated machining depth of the workpiece. When a certain machining point is currently ground based on the above, the grinding burn depth of the workpiece in the grinding of the same machining point (hereinafter referred to as pre-grinding ) one rotation before the workpiece is calculated. Based on the calculated grinding burn depth in the pre-grinding and the removal amount calculated in the current grinding (hereinafter referred to as the current grinding) at the machining point, the grinding burn depth in the current grinding is calculated. A new grinding burn depth calculation step for calculating the new grinding burn depth in the current grinding based on the calculated remaining grinding burn depth in the current grinding and the grinding burn depth calculated in the current grinding. To be equipped. As a result, the same effect as the effect of the above-mentioned grinding process simulation device can be obtained.

It is a figure which shows the grinding processing simulation apparatus and grinding apparatus of this embodiment. It is a block block diagram of a grinding processing simulation apparatus. It is a flowchart which shows the simulation method of the grinding burn depth calculation. It is a flowchart which shows the simulation method of chatter determination. It is a schematic diagram which shows a grindstone and a work piece. It is a figure which shows the outer edge line of a work piece and a grindstone represented by a line segment. It is a microscopic schematic diagram of a grinding point in a grinding process. It is a figure which shows the relationship between the maximum temperature of the simulated geographic feature and the depth from the surface of the geographic feature. It is a figure which shows the new grinding burn when the grinding burn residue of the present grinding is larger than the grinding burn, and the re-hardening layer of the grinding burn remains is larger than the re-hardening layer of the grinding burn. It is a figure which shows the new grinding burn when the grinding burn residue of the present grinding is larger than the grinding burn, and the re-hardening layer of the grinding burn remains is smaller than the re-hardening layer of the grinding burn. It is a figure which shows the new grinding burn when the grinding burn residue of the present grinding is smaller than the grinding burn, and the re-hardening layer of the grinding burn remains is smaller than the re-hardening layer of the grinding burn. It is a figure which shows the new grinding burn when the grinding burn residue of the present grinding is smaller than the grinding burn, and the re-hardening layer of the grinding burn remains is smaller than the re-hardening layer of the grinding burn. It is a figure which shows the grinding residue of the present grinding when the removal amount of the present grinding is smaller than the grinding burn of a pre-grind, and the re-hardening layer of the grinding burn of a pre-grind is larger. It is a figure when the removal amount of the current grinding is larger than the grinding burn of the pre-grinding. It is a figure which shows the display example at the time of superimposing the new grinding burn of the present grinding on the workpiece. It is a figure which shows the display example when chatter is superposed on the workpiece.

(1. Configuration of grinding processing simulation device and grinding device)
The grinding process simulation device and the grinding device of the present embodiment will be described with reference to the drawings. As shown in FIG. 1, the grinding process simulation device 1 is a device separate from the grinding device 2, and is communicably connected to the control device 24 as shown by the dotted line in the drawing. The grinding process simulation device 1 may be built in the control device 24. Further, the grinding processing simulation device 1 can be an embedded system such as a PLC (Programmable Logic Controller) or a CNC (Computer Numerical Control) device, or can be a personal computer or a server.

The grinding device 2 includes a grindstone wheel 21, a grindstone base 22, a spindle base 23, and a control device 24. Although not shown, the grinding device 2 is provided with a cooling device that cools the periphery of the grinding point P with coolant. The grinding device 2 grinds the peripheral surface of the workpiece W by bringing the peripheral surface of the grindstone 21 rotationally driven by the grindstone 22 into contact with the peripheral surface of the workpiece W rotationally driven by the spindle 23. Perform processing.

The grindstone wheel 21 is formed in a disk shape by a large amount of abrasive grains, and is rotatably supported by the grindstone base 22 around the grindstone axis Cg. The grindstone stand 22 rotates the grindstone wheel 21 around the grindstone axis Cg in response to a command from the control device 24. Further, the grindstone base 22 moves the grindstone wheel 21 in the Cg direction and the feed direction (X-axis direction) of the grindstone wheel 21 according to a command from the control device 24. The spindle base 23 may be moved in the feed direction (X-axis direction) with respect to the grindstone base 22.

The headstock 23 rotatably supports the columnar workpiece W around the spindle Cw, and rotates the workpiece W around the spindle Cw according to a command from the control device 24. The control device 24 commands the grindstone base 22 and the headstock 23 to control the relative position between the grindstone 21 and the workpiece W and the rotation speeds of the grindstone 21 and the workpiece W. When the workpiece W has a cam shape or an eccentric shape, the control device 24 also controls the rotation angle of the workpiece W.

As shown in FIG. 2, the grinding process simulation device 1 includes a workpiece shape storage unit 101, a grindstone shape storage unit 102, a command value storage unit 103, a relative position calculation unit 104, and a removal amount calculation unit 105. The workpiece shape changing unit 106, the grinding resistance calculation unit 107, the rigidity storage unit 108, the displacement amount calculation unit 109, the relative position correction unit 110, the machining condition storage unit 111, and the thermal energy calculation unit 112 are distributed. It includes a ratio calculation unit 113, a grinding burn depth calculation unit 114, a new grinding burn depth calculation unit 115, a chatter determination unit 116, a display control unit 117, and a display device 118.

The peripheral surface shape of the workpiece W is stored in the workpiece shape storage unit 101. That is, immediately before the start of the simulation, the peripheral surface shape of the workpiece W in the unground state is stored. For example, a circular shape that can be seen from the diameter of the workpiece is stored. The grindstone shape storage unit 102 stores the peripheral surface shape of the grindstone wheel 21. For example, a circular shape that can be seen from the diameter of the grindstone immediately before the start of grinding is stored.

The command value storage unit 103 stores the command value for the grinding device 2 in the grinding process. As shown in FIG. 1, the command value is the X-axis line between the main axis Cw (rotation center (axis center)) of the workpiece W and the grindstone axis Cg (rotation center (axis center)) of the grindstone 21 at a certain time. The X-axis value is a value that commands the separation distance in the direction, and the C-axis value (C = ωt) is a value that commands the rotation angle of the workpiece W at a certain time. Note that ω is the angular velocity of the geographic feature W. The command value is calculated based on grinding conditions such as the number of rotations of the workpiece, the number of rotations of the grindstone, and the feed amount (feed speed) of the grindstone 21 stored in the machining condition storage unit 111.

The relative position calculation unit 104 calculates the distance between the rotation center Cw of the workpiece W and the rotation center Cg of the grindstone 21 in the X-axis direction based on the command value stored in the command value storage unit 103. That is, the X-axis separation distance X is calculated as shown in the equation (1).

Ｘｏは加工開始位置におけるＸ軸値であり、Ｖｘは砥石車送り速度であり、Ａｉは偏心などに起因する振動片振幅であり、Ｎは考慮する最大次数であり、ｆは振動周波数である。

Xo is the X-axis value at the machining start position, Vx is the grindstone feed rate, Ai is the amplitude of the vibrating piece due to eccentricity or the like, N is the maximum order to be considered, and f is the vibration frequency.

In the formula (1), the value excluding the third term corresponds to the command value (X-axis value) at time t. The third term of the equation (1) is added in order to consider the periodic vibration due to the eccentricity of the grindstone 21 or the workpiece W. As will be described later, the relative position calculation unit 104 further adds or subtracts the displacement amount Xn to the equation (1) by the relative position correction unit 110 to calculate the X-axis separation distance.

The removal amount calculation unit 105 is a peripheral surface shape of the workpiece W stored in the geographic feature storage unit 101, a peripheral surface shape of the grindstone 21 stored in the grindstone shape storage unit 102, and a relative position calculation unit 104. The amount of the workpiece W removed by the grindstone 21 is calculated based on the calculated X-axis separation distance. As shown in FIG. 5, the removal amount is the volume of the portion (hatched portion in FIG. 5) where the grindstone 21 and the workpiece W interfere with each other.

The removal amount calculation unit 105 geometrically calculates the removal amount by arithmetic processing. That is, as shown in FIG. 6, the work shape storage unit 101 recognizes the shape of the work W by a plurality of line segment groups on polar coordinates with the rotation center Cw of the work W as the origin O. That is, the workpiece shape storage unit 101 has a plurality of lines connecting the division point (white point in the figure) on the peripheral edge of the workpiece W divided by the equiangular angle (α) and the rotation center Cw (origin O) of the workpiece W. The group is stored as the peripheral surface shape of the work W. Then, the dividing point (white point in the figure) is recognized as the end point of the line segment before the work W is removed by the grindstone 21.

Then, the removal amount calculation unit 105 determines an intersection (black point in the figure) between the line segment of the workpiece W and the outer edge line 21A of the grindstone 21 from the X-axis separation distance and the peripheral surface shape of the grindstone 21. (The black point in the figure) is recognized as the end point of the line segment after the work piece W is removed by the grindstone 21. Then, the removal amount calculation unit 105 determines the end points b1 and b2 after removal of the line segment having the end points a1 and a2 from the area of the triangle ΔOa1a2 composed of the adjacent end points a1 and a2 and the origin O among the end points before removal. The area of the triangle ΔOb1b2 consisting of the origin O and the origin O is subtracted.

Then, the removal amount calculation unit 105 integrates the difference in the area for each line segment, and multiplies the integrated value by the thickness of the workpiece W to calculate the removal amount. The above calculation can be performed at high speed with a small load by using the area of the triangle (side x side x sinα). Then, by reducing the angle α, the calculation can be performed more accurately. However, the quadrangle a1a2b1b2 may be directly obtained.

The work shape changing unit 106 changes the peripheral surface shape of the work W stored in the work shape storage unit 101 based on the removal amount calculated by the removal amount calculation unit 105. That is, the peripheral surface shape of the work piece W stored in the work piece shape storage unit 101 is updated to the shape after removal. That is, the workpiece shape changing unit 106 updates the peripheral surface shape of the workpiece W after being scraped, assuming that all the parts of the removal amount calculated by the removal amount calculation unit 105 have been scraped off by grinding.

This update of the geographic shape will be reflected in the next removal amount calculation. That is, the shaded portion in FIG. 5 schematically shows the removal amount immediately after the start of grinding (t1), but the removal amount at the next moment t1 + Δt is the work after removal (excluding the shaded portion). Calculated based on the shape of the object.

The grinding resistance calculation unit 107 calculates the grinding resistance Fn in the X-axis direction in the grinding process based on the removal amount calculated by the removal amount calculation unit 105. First, the grinding resistance calculation unit 107 calculates the removal amount J per unit time based on the removal amount. Then, the removal amount J per unit time is multiplied by the grinding characteristic kc in the X-axis direction determined based on the material of the workpiece W and the state of the peripheral surface of the grindstone 21, and the grinding resistance in the X-axis direction is multiplied. Calculate Fn (Fn = kc · J). Here, the grinding characteristic kc in the X-axis direction is stored in advance by experiments, analyzes, or the like.

The removal amount J per unit time is also referred to as grinding efficiency. The grinding characteristics kc have a substantially linear relationship such that the grinding resistance Fn in the X-axis direction increases as the removal amount J per unit time increases. The relationship between the grinding characteristics kc changes when the grindstone 21 is worn, for example. Specifically, when the grindstone 21 is worn, the grinding resistance Fn in the X-axis direction changes with respect to the removal amount J per unit time.

The rigidity storage unit 108 stores the rigidity of the workpiece and the rigidity of the grindstone. The work piece rigidity corresponds to the amount of displacement of the work piece W in the X-axis direction when a force in the X-axis direction is applied to the work piece W in a state of being supported by the headstock 23 of the grinding device 2. be. For example, the work piece rigidity is the reciprocal of the displacement amount of the work piece W in the X-axis direction. This workpiece rigidity is calculated in advance by actual measurement. For example, the work W is attached to the headstock 23, a measuring instrument (acceleration meter) is placed on one side of the work W in the X-axis direction, and the work W is hammered from the other side in the X-axis direction. The object rigidity can be obtained.

Then, based on the actual measurement, the rigidity of the workpiece can be expressed as a transfer function f1. That is, the rigidity storage unit 108 stores the rigidity of the workpiece as a transfer function f1. When the grinding device 2 is provided with a rest (work rest), the actual measurement may be performed in a state where the workpiece W is further supported by the rest. When the work W is supported by the rest, the amount of displacement of the work W in the X-axis direction when a force in the X-axis direction is applied to the work W becomes small. That is, when the work W is supported by the rest, the work rigidity increases.

Further, the rigidity of the grindstone corresponds to the amount of displacement of the grindstone 21 in the X-axis direction when a force in the X-axis direction is applied to the grindstone 21 in a state of being supported by the grindstone base 22 of the grinding device 2. It is a thing. For example, the rigidity of the grindstone is the reciprocal of the amount of displacement of the grindstone 21 in the X-axis direction. The rigidity of the grindstone is expressed as a transfer function f2 based on the same actual measurement as described above. Therefore, the rigidity storage unit 108 stores the rigidity of the grindstone as a transfer function f2.

In the actual measurement of the grindstone wheel rigidity, the grindstone wheel rigidity may be obtained by hammering the grindstone shaft of the grindstone stand 22 with the grindstone wheel 21 removed from the grindstone base 22. As a result, the rigidity of the grindstone can be approximated without damaging the peripheral surface of the grindstone 21.

The displacement amount calculation unit 109 stores the displacement amount Xn in which the grindstone 21 and the workpiece W are displaced relative to each other in the X-axis direction due to the grinding resistance Fn, and the workpiece rigidity and the grindstone rigidity stored in the rigidity storage unit 108. Calculate based on. Displacement can be determined from rigidity and resistance. Therefore, the displacement amount Xn can be calculated from the grinding resistance Fn, the rigidity of the workpiece (transfer function f1), and the rigidity of the grindstone (transfer function f2).

For example, the workpiece displacement amount X1 can be obtained by X1 = Fn / f1, and the grindstone displacement amount X2 can be obtained by X2 = Fn / f2. In general, the rigidity of the grindstone is much higher than the rigidity of the workpiece, so the displacement amount Xn may be obtained without considering the rigidity of the grindstone. However, as described above, the displacement amount Xn can be calculated with higher accuracy by considering the rigidity of the grindstone.

The relative position correction unit 110 corrects the X-axis separation distance in the relative position calculation unit 104 based on the displacement amount Xn calculated by the displacement amount calculation unit 109. That is, the relative position correction unit 110 further adds the displacement amount Xn to the equation (1). Then, the relative position calculation unit 104 calculates the X-axis separation distance at the next moment t1 + Δt by using the equation (1) in which the displacement amount Xn is added by the relative position correction unit 110. The displacement amount Xn due to the grinding resistance Fn is not taken into consideration in the X-axis separation distance only in the equation (1), but the displacement amount Xn is obtained by adding the displacement amount Xn to the equation (1) by the relative position correction unit 110. Is corrected to a value that takes into account.

As shown in the equation (2), the thermal energy calculation unit 112 has the relative speed of the grindstone 21 with respect to the workpiece W at the grinding point P and the grinding resistance in the tangential direction (Z-axis direction) calculated by the grinding resistance calculation unit 107. Multiply by Ft to calculate the total grinding thermal energy Q by grinding. Here, V is the peripheral speed of the grindstone 21 at the grinding point P, and v is the peripheral speed of the workpiece W at the grinding point P. The peripheral speed can be calculated based on the diameter and the number of revolutions. The equation (2) is for an upcut, and in the case of a downcut, the relative velocity is (Vv).

The grinding resistance Ft may be a value input (set) by an operator or the like, or may be a value calculated by calculation. In this embodiment, the grinding resistance Ft calculated in advance from the command value is provided as a database. Then, the grinding resistance Ft is calculated from the input command value using the database.

Here, as shown in FIG. 7, when the grinding process is viewed microscopically, the grinding heat energy generated by the grinding process is plastic deformation on the shear surface Wa and friction between the abrasive grains 21a and the chips Wp on the rake surface Wb. It can be said that this is caused by the friction between the abrasive grains 21a and the workpiece W on the flank Wc. That is, the thermal energy calculation unit 112 calculates the total grinding thermal energy Q, which is the total of the grinding thermal energy generated on the shear surface Wa, the rake surface Wb, and the flank surface Wc.

The distribution ratio calculation unit 113 calculates the distribution ratio Rw of the thermal energy received by the workpiece W out of the total grinding thermal energy Q calculated by the thermal energy calculation unit 112. As shown in FIG. 7, the grinding heat energy generated on the sheared surface Wa is distributed to the workpiece W and the chips Wp, and the grinding heat energy generated on the rake face Wb is distributed to the abrasive grains 21a and the chips Wp and escapes. The grinding heat energy generated on the surface Wc is distributed to the workpiece W and the abrasive grains 21a. Therefore, the workpiece W distributes thermal energy from the shear surface Wa and the flank surface Wc except for the rake face Wb.

Therefore, as shown in the equation (3), the distribution ratio Rw of the thermal energy received by the workpiece W is the distribution ratio Rwa of the thermal energy received by the workpiece W among the grinding heat energy on the shear surface Wa and the flank surface Wc. It can be expressed using the distribution ratio Rwc of the thermal energy received by the workpiece W among the grinding thermal energy.

ここで、Ｆｔｃは切粉Ｗｐにおける接線抵抗であり、Ｆｎｃは切粉Ｗｐにおける法線抵抗であり、βは砥粒すくい角であり、φはせん断角であり、Ｆｔｓｌは逃げ面Ｗｃにおける接線抵抗であり、Ｆｎｓｌは、逃げ面Ｗｃにおける法線抵抗である。図７では、Ｆｔ＝Ｆｔｃ＋Ｆｔｓｌ、Ｆｎ＝Ｆｎｃ＋Ｆｎｓｌとなる。

Here, Ftc is the tangential resistance at the chip Wp, Fnc is the normal resistance at the chip Wp, β is the abrasive grain rake angle, φ is the shear angle, and Ftsl is the tangential resistance at the flank Wc. And Fnsl is the normal resistance at the flank Wc. In FIG. 7, Ft = Ftc + Ftsl and Fn = Fnc + Fnsl.

fa (Ftc, Fnc, β, φ) is a function representing the resistance component to the relative velocity (V + v) generated in the shear plane Wa. That is, fa (Ftc, Fnc, β, φ) is the resistance component when the grinding heat energy (shear velocity × shear resistance) on the shear surface Wa is expressed by multiplying the relative velocity (V + v) and the resistance component. It is a function to represent.

The shear resistance and the shear rate can be expressed using the tangential resistance Ftc in the chips Wp, the normal resistance Fnc in the chips Wp, the abrasive grain rake angle β, and the shear angle φ. The distribution ratio calculation unit 113 calculates the distribution ratio Rw by the equation (3). The distribution ratios Rwa and Rwc are expressed by equations (4) and (5) using Jaeger's theory of transfer heat source (JC Jaeger: Proceedings of Royal Society of New South Wales, vol.76, (1942) 203). be able to.

ここで、ｇ_ｍは最大砥粒切り込み深さであり、ｆａ（β，φ）は、「せん断速度」に対する「相対速度（Ｖ＋ｖ）のせん断面Ｗａ法線方向成分」の割合を表す関数であり、ｋｗは工作物Ｗの熱伝導率であり、ｌｇは逃げ面Ｗｃの長さであり、ｋｇは砥粒２１ａの熱伝導率である。なお、砥粒すくい角β、せん断角φ、及び、逃げ面Ｗｃの長さｌｇなどは、砥石車２１表面の観測結果等に基づいて見積もられた値を用いている。

Here, g _m is the maximum abrasive grain cutting depth, and fa (β, φ) is a function representing the ratio of the “shear surface Wa normal direction component of the relative speed (V + v)” to the “shear speed”. , Kw is the thermal conductivity of the workpiece W, lg is the length of the flank Wc, and kg is the thermal conductivity of the abrasive grains 21a. The abrasive grain rake angle β, the shear angle φ, and the length lg of the flank surface Wc are estimated values based on the observation results of the surface of the grindstone wheel 21 and the like.

The grinding burn depth calculation unit 114 first calculates the temperature of the workpiece W based on the total grinding heat energy Q calculated by the thermal energy calculation unit 112 and the distribution ratio Rw calculated by the distribution ratio calculation unit 113. That is, by multiplying the total thermal energy Q and the distribution ratio Rw, the total thermal energy (Rw × Q) received by the workpiece W by the grinding process can be obtained.

Then, as shown in the equation (6), the heat flux q _w (heat energy per unit contact area) with respect to the workpiece W can be obtained from this total thermal energy (Rw × Q). lc is the contact arc length, and b is the width of the workpiece W (the length in the spindle direction).

Here, using the theory of the mobile heat source, the temperature θw (X, Z) at the position (X, Z) of the workpiece W can be obtained as shown in the equation (7). The coordinates X indicate a position on a straight line passing through the grinding point P of the workpiece W and the center point of the workpiece W. That is, the coordinates X indicate the depth of the workpiece W from the surface. Further, the coordinate Z indicates the position on the tangent line of the grinding point P of the workpiece W.

ここで、Ｋoは第２種０次の修正ベッセル関数であり、ｅｒｆは誤差関数であり、ｅｒｆｃは補誤差関数である。

Here, Ko is a second-order 0th-order modified Bessel function, erf is an error function, and erfc is a complementary error function.

In the first term of the equation (7), the rising temperature at each position of the work W due to the total heat energy received by the work W is calculated. In the second term of the formula (7), the decrease temperature at each position of the workpiece W, which decreases due to the cooling effect of the coolant, is calculated. The third term of the equation (7), that is, θwo (X, Z) is the initial temperature at each position of the workpiece W.

In the theoretical setting of the geographic feature temperature, it is considered that the high temperature and the minute grinding point temperature are instantly conducted to the surroundings to form a macroscopic temperature distribution, and the temperature distribution in the contact arc is examined. Further, X, Z, L, and the convection heat transfer coefficient H are dimensionless quantities as shown in the equation (8). Note that h is the convection heat transfer coefficient of the coolant.

In this way, the grinding burn depth calculation unit 114 first calculates the temperature θw (X, Z) at each position (X, Z) of the workpiece W by the equation (7). As a result, the temperature distribution of the workpiece W is calculated. Then, based on the calculated temperature θw (X, Z), the maximum temperature θw, max (X) at each depth of the workpiece W is calculated.

The temperature θw (X) at the depth X of the workpiece W is not always uniform in the circumferential direction of the workpiece W. Therefore, the maximum temperatures θw and max (X) at each depth are obtained. Here, the above-mentioned maximum temperature calculation result is shown in FIG. 8 as an example. FIG. 8 is a diagram showing the relationship between the maximum temperature of the workpiece W calculated by the grinding burn depth calculation unit 114 and the depth from the surface of the workpiece W. The vertical axis is the maximum temperature, and the horizontal axis is the depth from the surface of the workpiece.

Here, the grinding burn depth calculation unit 114 is set with the first and second temperature thresholds θ1 and θ2 for determining the grinding burn based on the metallographic properties of the workpiece W. The first temperature threshold value θ1 is set to a temperature at which “tempering (softening layer)” of grinding burn is determined. The second temperature threshold value θ2 is set to a temperature at which “re-quenching (re-hardened layer (white layer))” of the grinding burn is determined.

The grinding burn depth calculation unit 114 is the depth from the surface of the workpiece W showing the maximum temperatures θw and max (X) larger than the first temperature threshold value θ1 and smaller than the second temperature threshold value θ2 (> θ1). Of X, the depth X1 from the surface of the deepest workpiece W is calculated. That is, the depth X1 from the surface of the workpiece W obtained here is the maximum X that satisfies the condition shown in the equation (9).

Next, the grinding burn depth calculation unit 114 determines the deepest depth X from the surface of the workpiece W showing the maximum temperatures θw and max (X) larger than the second temperature threshold value θ2. The depth X2 from the surface is calculated. That is, the depth X2 from the surface of the workpiece W obtained here is the maximum X that satisfies the condition shown in the equation (10).

The new grinding burn depth calculation unit 115 performs the current grinding based on the grinding burn depth in the pre-grind calculated by the grinding burn depth calculation unit 114 and the removal amount in the current grinding calculated by the removal amount calculation unit 105. Calculate the unburned depth of grinding. Then, the new grinding burn depth in the current grinding is calculated based on the calculated remaining grinding burn depth in the current grinding and the grinding burn depth in the current grinding calculated by the grinding burn depth calculation unit 114.

Pre-grinding is, for example, grinding of the same machining point before one rotation of the workpiece W when a certain machining point is currently ground. For example, as shown in FIG. 9A, the residual grinding burn depth (d8-d1) in the current grinding is the grinding burn depth (d8) in the pre-grinding and the removal amount (depth from the surface of the workpiece W) in the current grinding. It is represented by the difference from the value (d1) converted to.

Here, the new grinding burn in the current grinding occurs by superimposing the grinding burn in the current grinding on the remaining portion of the grinding burn in the current grinding. The inventor has found that the new grinding burn depth in the current grinding is greatly related to the grinding burn depth in the current grinding and the grinding burn depth in the current grinding.

That is, whether the grinding burn depth in the pre-grinding is larger or smaller than the removal amount in the current grinding, and the depth of the re-hardened layer (white layer) in the grinding burn depth in the pre-grinding is the removal amount in the current grinding. The unburned depth of grinding in the current grinding changes depending on whether or not it is larger than.

Then, whether the grinding burn depth in the current grinding is larger or smaller than the grinding burn depth in the current grinding, and the depth of the re-hardened layer (white layer) in the grinding burn depth in the current grinding is the current grinding. The new grinding burn depth in the current grinding changes depending on whether it is larger or smaller than the depth of the re-hardened layer (white layer) among the grinding burn depths in the above.

For example, in FIGS. 9A-9D, the grinding burn depth (d8) in the pre-grinding is larger than the removal amount (d1) in the current grinding, and the re-hardened layer (white layer) in the grinding burn depth in the pre-grinding. Depth (d3) is larger than the removal amount (d1) in the current grinding.

In FIG. 9A, the grinding burn depth (d7-d1) in the current grinding is smaller than the grinding burn depth (d8-d1) in the current grinding, and the grinding burn depth (d7-d1) in the current grinding is shown. ), The depth of the re-cured layer (white layer) (d2-d1) is the depth of the re-cured layer (white layer) (d3-d1) of the unburned depth (d8-d1) in the current grinding. If it is smaller than.

In this case, the depth (d2-d1) of the re-hardened layer (white layer) in the new grinding burn depth (d8-d1) in the current grinding is the re-grinding burn depth (d7-d1) in the current grinding. It becomes the same depending on the depth (d2-d1) of the cured layer (white layer). The depth of the softened layer (d8-d2) in the new grinding burn depth (d8-d1) in the current grinding is the depth of the softened layer (d8-d1) in the remaining grinding burn depth (d8-d1) in the current grinding. It is determined depending on the depth of the softened layer (d7-d2) among the d8-d3) and the grinding burn depth (d7-d1) in the current grinding.

Further, in FIG. 9B, the grinding burn depth (d6-d1) in the current grinding is smaller than the grinding burn depth (d8-d1) in the current grinding, and the grinding burn depth (d6-d1) in the current grinding is shown. ), The depth of the re-cured layer (white layer) (d5-d1) is the depth of the re-cured layer (white layer) (d3-d1) of the unburned depth (d8-d1) in the current grinding. If it is larger than.

In this case, the depth (d5-d1) of the re-hardened layer (white layer) in the new grinding burn depth (d8-d1) in the current grinding is the re-grinding burn depth (d6-d1) in the current grinding. It becomes the same depending on the depth (d5-d1) of the cured layer (white layer). The depth of the softened layer (d8-d5) in the new grinding burn depth (d8-d1) in the current grinding is the depth of the softened layer (d8-d3) in the remaining grinding burn depth in the current grinding. It is also determined depending on the depth of the softened layer (d6-d5) of the grinding burn depth (d6-d1) in the current grinding.

Further, in FIG. 9C, the grinding burn depth (d9-d1) in the current grinding is larger than the grinding burn depth (d8-d1) in the current grinding, and the grinding burn depth (d9-d1) in the current grinding is shown. ), The depth of the re-cured layer (white layer) (d4-d1) is the depth of the re-cured layer (white layer) (d3-d1) of the unburned depth (d8-d1) in the current grinding. If it is larger than.

In this case, the depth (d4-d1) of the re-hardened layer (white layer) in the new grinding burn depth (d9-d1) in the current grinding is the re-grinding burn depth (d9-d1) in the current grinding. It becomes the same depending on the depth (d4-d1) of the cured layer (white layer). The depth of the softened layer (d9-d4) in the new grinding burn depth (d9-d1) in the current grinding is the depth of the softened layer (d9) in the grinding burn depth (d9-d1) in the current grinding. It becomes the same depending on −d4).

Further, in FIG. 9D, the grinding burn depth (d9-d1) in the current grinding is larger than the grinding burn depth (d8-d1) in the current grinding, and the grinding burn depth (d9-d1) in the current grinding is shown. ), The depth of the re-cured layer (white layer) (d2-d1) is the depth of the re-cured layer (white layer) (d3-d1) of the unburned depth (d8-d1) in the current grinding. If it is smaller than.

In this case, the depth (d2-d1) of the re-hardened layer (white layer) in the new grinding burn depth (d9-d1) in the current grinding is the re-grinding burn depth (d9-d1) in the current grinding. It becomes the same depending on the depth (d2-d1) of the cured layer (white layer). The depth of the softened layer (d9-d2) in the new grinding burn depth (d9-d1) in the current grinding is the depth of the softened layer (d9) in the grinding burn depth (d9-d1) in the current grinding. It becomes the same depending on −d2).

As shown in FIG. 10A, the grinding burn depth (d8) in the pre-grinding is larger than the removal amount (d1) in the current grinding, and the re-hardened layer (white layer) in the grinding burn depth in the pre-grinding. When the depth (d3) is smaller than the removal amount (d10) in the current grinding, the re-hardened layer (white layer) is removed from the grinding burn in the pre-grinding, and only the softened layer remains. Further, as shown in FIG. 10B, when the grinding burn depth (d8) in the pre-grinding is smaller than the removal amount (d1) in the current grinding, all the grinding burn in the pre-grinding is removed.

The chatter determination unit 116 determines the presence or absence of chatter based on the peripheral surface shape (processed shape) of the changed workpiece W stored in the workpiece shape storage unit 101. The chatter determination unit 116 stores the peripheral surface shape of the workpiece W to be obtained by grinding, that is, the peripheral surface shape (ideal shape) of the ideal workpiece W intended by the operator or the like. The chatter determination unit 116 can find out the surface roughness of the ground surface in the machined shape by comparing the machined shape with the ideal shape.

The chatter determination unit 116 determines that there is chatter when the processed shape and the ideal shape do not match. The determination may be made every one rotation (one cycle) of the workpiece W, at a certain timing during machining, or at the final shape (shape after grinding). When the chatter determination unit 116 determines that there is chatter, the chatter determination unit 116 further calculates the chatter amount. The amount of chatter can be calculated from the surface roughness of the ground surface in the machined shape. The amount of chatter can be expressed by the number of chatters on the entire peripheral surface or the protrusion length of chatter (the amount of protrusion outward in the radial direction). In the present embodiment, the maximum protrusion length of chatter is calculated as the chatter amount.

The display control unit 117 displays the new grinding burn depth calculated by the new grinding burn depth calculation unit 115 on the display device 118. Further, the chatter amount calculated by the chatter determination unit 116 is displayed on the display device 118. For example, as shown in FIGS. 11 and 12, in the display device 118, the peripheral surface shape of the work W is a division point (black point in the figure) on the peripheral edge of the work W divided by an equiangular angle (α) and the work. It is represented by a plurality of line segment groups connecting the rotation center Cw (origin O) of W. In this example, a part of the workpiece W is displayed, but the entire workpiece W may be displayed.

As shown in FIG. 11, the display control unit 117 superimposes and displays the new grinding burn depth on the peripheral surface shape of the workpiece W. That is, the rehardened layer (white layer) Ta is shown between the dividing point (black point in the figure) and the white point in the figure on the peripheral edge, and the softened layer Tb is shown between the white point in the figure and the gray point in the figure. The display control unit 117 can display the new grinding burn depth at an arbitrary time point in the grinding process. Further, as shown in FIG. 12, the display control unit 117 superimposes the chatter amount S on the peripheral surface shape of the workpiece W and displays it.

(2. Operation of grinding simulation equipment)
Next, the grinding burn simulation operation by the grinding processing simulation device 1 will be described with reference to the drawings. The removal amount calculation unit 105 is a peripheral surface shape of the workpiece W stored in the geographic shape storage unit 101, a peripheral surface shape of the grindstone 21 stored in the grindstone shape storage unit 102, and a relative position calculation unit 104. Based on the calculated X-axis separation distance, the removal amount of the workpiece W by the grindstone 21 is calculated (step S1 in FIG. 3, removal amount calculation step).

Then, the grinding resistance calculation unit 107 calculates the grinding resistance Fn in the X-axis direction in the grinding process based on the removal amount calculated by the removal amount calculation unit 105 (step S2 in FIG. 3, the grinding resistance calculation step). The thermal energy calculation unit 112 calculates the total grinding heat energy Q by grinding by multiplying the relative speed of the grindstone 21 with respect to the workpiece W at the grinding point P by the grinding resistance Fn calculated by the grinding resistance calculation unit 107. (Step S3 of FIG. 3, thermal energy calculation step).

Then, the grinding burn depth calculation unit 114 works based on the grinding thermal energy calculated by the thermal energy calculation unit 112, the contact arc length lc between the workpiece W and the grindstone 21, and the depth of the workpiece W. The temperature at the depth from the surface of the object W is calculated (step S4 in FIG. 3, temperature calculation step). Then, the grinding burn depth calculation unit 114 calculates the grinding burn depth of the workpiece W based on the calculated temperature of the depth from the surface of the workpiece W. First, the grinding burn depth in the pre-grinding Is calculated, and the grinding burn depth in the current grinding is calculated based on the grinding burn depth in the pre-grinding and the removal amount calculated by the removal amount calculation unit 105 in the current grinding (step S5 in FIG. 3, New grinding burn depth calculation process).

Then, the grinding burn depth of the workpiece W in the current grinding is calculated (step S6 in FIG. 3, the new grinding burn depth calculation step), and the calculated remaining grinding burn depth in the current grinding and the calculated current grinding Based on the grinding burn depth, the new grinding burn depth in the current grinding is calculated (step S7 in FIG. 3, the new grinding burn depth calculation step).

Then, it is determined whether or not the grinding process is completed (step S8 in FIG. 3), and if the grinding process is not completed, the process returns to step S1 and the above process is repeated. On the other hand, when the grinding process is completed in step S8, the display control unit 117 displays the new grinding burn depth on the display device 118 (step S9 in FIG. 3), and ends all the processes.

Next, the chatter simulation operation by the grinding process simulation device 1 will be described with reference to the drawings. The removal amount calculation unit 105 is a peripheral surface shape of the workpiece W stored in the geographic feature storage unit 101, a peripheral surface shape of the grindstone 21 stored in the grindstone shape storage unit 102, and a relative position calculation unit 104. Based on the calculated X-axis separation distance, the amount of the workpiece W removed by the grindstone 21 is calculated (step S11 in FIG. 4).

Since the position of the grindstone 21 is corrected, the workpiece shape changing unit 106 determines whether or not to change the shape of the workpiece based on the calculated removal amount (step S12 in FIG. 4), and determines whether or not to change the shape of the workpiece (step S12 in FIG. 4). When is not changed, the grinding resistance calculation unit 107 calculates the grinding resistance Fn in the X-axis direction in the grinding process based on the removal amount calculated by the removal amount calculation unit 105 (step S13 in FIG. 4).

Then, the displacement amount calculation unit 109 calculates the displacement amount Xn in which the grindstone 21 and the workpiece W are relatively displaced in the relative movement direction due to the grinding resistance calculated by the grinding resistance calculation unit 107 (FIG. 4). Step S14). The relative position correction unit 110 corrects the X-axis separation distance in the relative position calculation unit 104 based on the displacement amount Xn calculated by the displacement amount calculation unit 109 (step S15 in FIG. 4).

Then, returning to step S11, the removal amount calculation unit 105 determines the peripheral surface shape of the workpiece W stored in the geographic shape storage unit 101 and the peripheral surface shape of the grindstone 21 stored in the grindstone shape storage unit 102. Then, the amount of the workpiece W removed by the grindstone 21 is calculated based on the corrected X-axis separation distance.

Since the work shape changing unit 106 corrected the position of the grindstone 21, the shape of the work W was changed based on the calculated removal amount (step S12 in FIG. 4), and the chatter determination unit 116 changed the work. Based on the shape of the object W, it is determined whether or not there is chatter, that is, whether or not the roundness of the workpiece W is within the standard (step S16 in FIG. 4). Here, the roundness refers to the difference in radius between two circles when the gap between the two concentric circles is minimized when the circular body is sandwiched between two concentric geometric circles.

When the chatter determination unit 116 determines that there is no chatter, the chatter determination unit 116 returns to step S11 and repeats the above-mentioned process. On the other hand, in step S16, when the chatter determination unit 116 determines that there is chatter, it performs frequency analysis on the shape of the workpiece W and determines the presence or absence of chatter from the periodic change of the shape (presence or absence of frequency peak). ). That is, frequency analysis such as FFT (Fast Fourier Transform) is performed on the shape of the workpiece W (step S17 in FIG. 4), and the relationship between the number of peaks (order) and the amplitude is obtained. Then, the display control unit 117 displays the relationship between the number of peaks (order) and the amplitude on the display device 118 (step S18 in FIG. 4).

The chatter determination unit 116 determines whether or not the number of peaks (order) is specified (step S19 in FIG. 4), and if it is determined that the number of peaks (order) is not specified, the process proceeds to step S21 and the number of peaks (order) is specified. When it is determined that is specified, the display control unit 117 displays the amplitude of each spindle rotation of the specified number of peaks (designated order) on the display device 118 (step S20 in FIG. 4). Then, it is determined whether or not the grinding process is completed (step S21 in FIG. 4), and if the grinding process is not completed, the process returns to step S11 and the above process is repeated. On the other hand, when the grinding process is completed in step S21, all the processes are completed.

Further, via a network (wireless, wired LAN, etc.) connected to the control device 24, the transmission / reception unit 119 of the grinding processing simulation device 1 determines the processing conditions of the grinding device 2 (the number of rotations of the workpiece W, the grindstone 21). Rotation speed, feed amount (feed speed) of the grindstone 21, sensors (current, voltage, temperature (including infrared sensor) and vibration (distortion sensor and vibration detection) of the rotary drive motor of the workpiece W and the grindstone 21 (Sensor, AE sensor, etc.)) is received and a simulation is performed, and from the result (no grinding burn, no chatter), machining condition information etc. is transmitted to the grinding device 2 and machining is performed under these machining conditions. As a result, it is possible to perform processing without grinding and burning of the workpiece W and chattering.

(3. Effect of the embodiment)
In the grinding processing simulation device 1 of the present embodiment, the rotationally driven grindstone 21 and the rotationally driven workpiece W are relatively moved so that the peripheral surface of the grindstone 21 is brought into contact with the peripheral surface of the workpiece W. In the grinding process for grinding the peripheral surface of the workpiece W, the grinding process simulation device 1 that simulates the grinding state of the workpiece W, and works with the grindstone 21 in the relative movement direction between the grindstone 21 and the workpiece W. Based on the removal amount calculation unit 105 that calculates the removal amount of the workpiece W by the grindstone 21 based on the relative position with the object W, the shape of the grindstone 21, and the shape of the workpiece W, and the calculated removal amount. The grinding resistance calculation unit 107 for calculating the grinding resistance in the grinding process is provided.

Further, the thermal energy calculation unit 112 that calculates the grinding heat energy based on the calculated grinding resistance and the relative speed of the grindstone 21 with respect to the workpiece W at the grinding point, and the calculated grinding heat energy, the workpiece W and the grindstone. The temperature at the machining depth of the workpiece W is calculated based on the contact arc length with the vehicle 21 and the machining depth of the workpiece W, and the machining is performed based on the calculated machining depth temperature of the workpiece W. Grinding burn depth in the current grinding based on the grinding burn depth calculation unit 114 that calculates the grinding burn depth of the object W, the grinding burn depth calculated in the pre-grinding, and the removal amount calculated in the current grinding. With the new grinding burn depth calculation unit 115, which calculates the new grinding burn depth in the current grinding based on the calculated remaining grinding burn depth in the current grinding and the grinding burn depth calculated in the current grinding. , Equipped with.

In this grinding processing simulation apparatus 1, the grinding burn depth in the current grinding is calculated based on the grinding burn depth calculated in the pre-grinding and the removal amount calculated in the current grinding. Then, the new grinding burn depth in the current grinding is calculated based on the calculated remaining grinding burn depth in the current grinding and the grinding burn depth calculated in the current grinding. As a result, even if the grinding burn in the pre-grinding cannot be completely removed by the current grinding and remains, the new grinding burn depth in the current grinding is calculated in consideration of the grinding burn-out depth in the current grinding. , The grinding burn depth of the workpiece W in the grinding process can be calculated more accurately. Further, since the grinding burn for each rotation of the workpiece W is calculated, the machining state can be grasped more accurately.

Further, since the new grinding burn depth calculation unit 115 continues the calculation process from the start to the end of the grinding process of the workpiece W, it is possible to grasp the state of the grinding burn during the grinding process (start of the grinding process of the workpiece W). Any machining point from to the end).
Further, the removal amount calculation unit 105 represents the peripheral surface shape of the workpiece W by a plurality of line segment groups connecting the division points on the peripheral edge of the workpiece W and the axial center of the workpiece W, and each line segment and the grindstone. Since the removal amount is calculated based on the intersection with the outer edge of the car 21 and the distance between the axis of the grindstone 21 and the axis of the workpiece W in the relative movement direction of the grindstone 21, the removal amount is calculated. It can be calculated easily.

Further, the new grinding burn depth calculation unit 115 grasps each depth of the regrinded layer and the softened layer in the grinding burn depth in the current grinding and the grinding burn depth in the current grinding, respectively, and grinds in the current grinding. Since the depth of the re-hardened layer is prioritized in the burn depth and the depths of the re-hardened layer and the softened layer in the new grinding burn depth are grasped, the grinding processing conditions can be changed with higher accuracy.

Further, since the grinding process simulation device 1 includes a workpiece shape changing portion 106 that changes the shape of the workpiece W based on the calculated removal amount, the calculation accuracy of the new grinding burn depth can be further improved. ..

Further, the grinding processing simulation device 1 uses the displacement amount calculation unit 109 for calculating the displacement amount in which the grindstone 21 and the workpiece W are relatively displaced in the relative movement direction due to the calculated grinding resistance, and the calculated displacement amount. Based on this, a relative position correction unit 110 that corrects the relative position between the grindstone 21 and the workpiece W in the next grinding, and a chatter determination unit 116 that determines the presence or absence of chatter based on the changed shape of the workpiece W. Therefore, the presence or absence of chatter can be grasped before grinding, and the production efficiency can be improved. Further, since the machining state of grinding burn and chatter can be simulated at the same time, the optimum machining conditions for grinding burn and chatter can be obtained at one time.

Further, the grinding processing simulation device 1 includes a transmission / reception unit 119 that receives processing condition information from the grinding device 2 and transmits the processing conditions to the grinding device 2 based on the result of the simulation in order to perform the simulation. By processing under these processing conditions, it is possible to perform processing that does not cause grinding burn or chattering of the workpiece W.

In the grinding processing simulation method of the present embodiment, the rotationally driven grindstone 21 and the rotationally driven workpiece W are relatively moved, and the peripheral surface of the grindstone 21 is brought into contact with the peripheral surface of the workpiece W for machining. In the grinding process for grinding the peripheral surface of the object W, this is a grinding process simulation method that simulates the grinding state of the workpiece W, and the grindstone 21 and the workpiece W in the relative movement direction between the grindstone 21 and the workpiece W The removal amount calculation step for calculating the removal amount of the workpiece W by the grindstone 21 based on the relative position of the grindstone 21, the shape of the grindstone 21, and the shape of the workpiece W, and the grinding process based on the calculated removal amount. It is provided with a grinding resistance calculation step for calculating the grinding resistance in the above.

Further, a thermal energy calculation step for calculating the grinding heat energy based on the calculated grinding resistance and the relative speed of the grindstone 21 with respect to the workpiece W at the grinding point, and the calculated grinding thermal energy, the workpiece W and the grindstone. Based on the temperature calculation process for calculating the temperature at the machining depth of the workpiece W based on the contact arc length with 21 and the machining depth of the workpiece W, and the calculated machining depth temperature of the workpiece W. Then, the grinding burn depth of the workpiece W in the pre-grinding is calculated, and the grinding burn depth in the current grinding is calculated based on the calculated grinding burn depth in the pre-grinding and the removal amount calculated in the current grinding. It is provided with a new grinding burn depth calculation step for calculating the new grinding burn depth in the current grinding based on the calculated remaining grinding burn depth in the current grinding and the grinding burn depth calculated in the current grinding. .. As a result, the same effect as that of the above-mentioned grinding process simulation device 1 can be obtained.

1: Grinding simulation device, 101: Work shape storage unit, 102: Grindstone shape storage unit, 103: Command value storage unit, 104: Relative position calculation unit, 105: Removal amount calculation unit, 106: Work shape change unit , 107: Grinding resistance calculation unit, 108: Rigidity storage unit, 109: Displacement amount calculation unit, 110: Relative position correction unit, 111: Machining condition storage unit, 112: Thermal energy calculation unit, 113: Distribution ratio calculation unit, 114 : Grinding burn depth calculation unit, 115: New grinding burn depth calculation unit, 116: Chatter judgment unit, 117: Display control unit, 118: Display device, 119: Transmission / reception unit 2: Grinding device, 21: Grindstone, 22: Grindstone stand, 23: Headstock, 24: Control device, W: Work piece, P: Grinding point

Claims (8)

In a grinding process in which a rotationally driven grindstone and a rotationally driven workpiece are relatively moved to bring the peripheral surface of the grindstone into contact with the peripheral surface of the workpiece, and the peripheral surface of the workpiece is ground. A grinding process simulation device that simulates the grinding state of the workpiece.
Based on the relative position of the grindstone and the workpiece in the relative movement direction of the grindstone and the workpiece, the shape of the grindstone, and the shape of the workpiece, the workpiece by the grindstone. A removal amount calculation unit that calculates the removal amount, and
A grinding resistance calculation unit that calculates the grinding resistance in the grinding process based on the calculated removal amount, and a grinding resistance calculation unit.
A thermal energy calculation unit that calculates the grinding thermal energy based on the calculated grinding resistance and the relative speed of the grindstone with respect to the workpiece at the grinding point.
Based on the calculated thermal energy of grinding, the contact arc length between the workpiece and the grindstone, and the machining depth of the workpiece, the temperature at the machining depth of the workpiece was calculated and calculated. A grinding burn depth calculation unit that calculates the grinding burn depth of the workpiece based on the temperature of the machining depth of the object,
When a certain machining point is currently being ground, the grinding burn depth calculated in grinding the same machining point one rotation before the workpiece (hereinafter referred to as pre-grinding ) and the current machining point of the machining point Based on the removal amount calculated in the grinding (hereinafter referred to as the current grinding ) , the residual grinding burn depth in the current grinding is calculated, and the calculated residual grinding burn depth in the current grinding and the calculation in the current grinding are calculated. A new grinding burn depth calculation unit that calculates the new grinding burn depth in the current grinding based on the grinding burn depth
A grinding machine simulation device. The grinding process simulation device according to claim 1, wherein the new grinding burn depth calculation unit continues the calculation process from the start to the end of the grinding process of the workpiece. The removal amount calculation unit represents the peripheral surface shape of the workpiece by a plurality of line segment groups connecting the division points on the peripheral edge of the workpiece and the axial center of the workpiece, and each of the line segments and the said. The removal amount is calculated based on the intersection with the outer edge line of the grindstone and the distance between the axis of the grindstone and the axis of the workpiece in the relative movement direction of the grindstone. Or the grinding process simulation apparatus according to 2. The new grinding burn depth calculation unit grasps each depth of the re-hardened layer and the softened layer at the grinding burn depth in the current grinding and the grinding burn depth in the current grinding, respectively, and the current grinding burn depth calculation unit. Based on the depth of the rehardened layer at the grinding burn depth in grinding, the rehardened layer at the new grinding burn depth is grasped, and the depth of the softened layer at least at the grinding burn depth in the current grinding. The grinding processing simulation apparatus according to any one of claims 1-3, which grasps the depth of the softened layer at the new grinding burn depth based on the above. The grinding processing simulation device is
A work shape changing unit that changes the shape of the work based on the calculated removal amount.
The grinding processing simulation apparatus according to any one of claims 1-4. The grinding processing simulation device is
A displacement amount calculation unit that calculates a displacement amount in which the grindstone wheel and the workpiece are displaced relative to each other in the relative movement direction due to the calculated grinding resistance.
A relative position correction unit that corrects the relative position between the grindstone and the workpiece in the next grinding based on the calculated displacement amount.
A chatter determination unit that determines the presence or absence of chatter based on the changed shape of the workpiece,
The grinding processing simulation apparatus according to claim 5. The grinding processing simulation device is
The invention according to any one of claims 1 to 6, further comprising a transmission / reception unit that receives machining condition information from the grinding apparatus and transmits the machining conditions to the grinding apparatus based on the result of the simulation in order to perform the simulation. The grinding process simulation device described. In a grinding process in which a rotationally driven grindstone and a rotationally driven workpiece are relatively moved to bring the peripheral surface of the grindstone into contact with the peripheral surface of the workpiece, and the peripheral surface of the workpiece is ground. This is a grinding process simulation method that simulates the grinding state of the workpiece.
Based on the relative position of the grindstone and the workpiece in the relative movement direction of the grindstone and the workpiece, the shape of the grindstone, and the shape of the workpiece, the workpiece by the grindstone. The removal amount calculation process for calculating the removal amount and
A grinding resistance calculation step of calculating the grinding resistance in the grinding process based on the calculated removal amount, and a grinding resistance calculation step.
A thermal energy calculation step of calculating the grinding thermal energy based on the calculated grinding resistance and the relative speed of the grindstone with respect to the workpiece at the grinding point.
A temperature calculation step of calculating the temperature at the machining depth of the workpiece based on the calculated grinding heat energy, the contact arc length between the workpiece and the grindstone, and the machining depth of the workpiece.
When a certain machining point is currently being ground based on the calculated machining depth temperature of the workpiece, the above-mentioned in grinding of the same machining point (hereinafter referred to as pre-grinding ) one rotation before the workpiece. The current grinding burn depth of the workpiece is calculated, and based on the calculated grinding burn depth in the pre-grinding and the removal amount calculated in the current grinding of the machining point (hereinafter referred to as the current grinding). The new grinding burn depth in the current grinding is calculated based on the calculated grinding burn depth in the current grinding and the grinding burn depth calculated in the current grinding. New grinding burn depth calculation process to be calculated and
A grinding process simulation method.

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